Was writing a detailed response and something on board took over my computer and redirected. Simple; Has it worked since you owned 45XLE? Lite on lower left dash say hi or low on when you have ac turned on? freon in system/any? takes 27lbs 134. will take 4 or 5 roof air minimun. stock is almost 96,000 btu cooling. roof tops are 15,000 each you do math. Isn't bus dark blue=add one roof top. Bob

Wouldn't take for my OTR in my 91 Prevost 8V92TA. Haven't noticed any change in fuel mileage in summer. Have read where a lot of the folks take um out. Why, don't know, if it's a factory install. Like anything else takes work to keep um going. I'd say fix it.

Could be freon. If it is very low the system won't let the compressor clutch engage. Might be some leaks in the system. On my 1989 Prevost my compressor needed rebuilding etc. Cost $4200.00 for complete system overhaul.

If your bus is insulated well (I have 2.25" of spray foam) and your windows are tinted, it doesn't take much to A/C the bus. Two of my 13,500btu will cool the bus to the mid 70's in 105 degree weather. Was once in 108 degree weather coming through Needles, Ca and I turned all three on. Looked back at my wife a half hour later and she had a sweater on! Considering I've had the three roof airs on the bus since '95 and except for cleaning the filters and replacing one external shroud, I've done nothing to them. I don't think anyone with over the road A/C can say that. Good Luck, TomC

OEM bus air is nice to have, but can be expensive to maintain. It is the biggest maintenance expense for commercial operators. When I looked after the hockey team's bus, it averaged $1000/year to recharge and fix. Could never find the slow leaks. If they found one (professional refrig. company), another one would appear soon. It was a 102D3 with not many miles. Some bus nuts have reported trouble free systems. But be aware just the same.

Have read where a lot of the folks take um out. Why, don't know, if it's a factory install.

Why have many of us removed them? In our case, the compressor was missing (removed) when we got the bus. Just the parts to rebuild our factory a/c to factory condition would have cost us 45% of what we paid for our bus, plus freon and labor. So it was an easy choice for us.

And the factory a/c system components are expensive, plus they weigh more than an ex mother-in-law. On our 32-year-old bus, chances of something else in the system developing a fault are high, and many a/c parts are now made of unobtanium.

Oh, and then there is the little detail of the proper type of freon for some of these old systems now being ILLEGAL.

I am having the same dilemma with our new to us 73 MCI 7 . The bus air has no freon in it so is obviously leaking. I am not going to fix it, looking at the system, it is 40 years old and has probably a hundred feet of piping and loads of places to leak, plus it holds like 20lbs of freon and it is really expensive to fill. We have 3 built in AC units that work great and almost never need maintenance. My only complaint is that we can only run one off the inverter so need to run the genset if it is really warm. I am going to put a small mini split AC unit up front, I have seen one of these that operate at 24vdc which may be best as it would leave me inverter power to run another one of the house units and not have to run the genset.

Factory AC is great if it works and useless if it doesn't, so it all comes down to cost of repair and maintenance. Once you get an estimate of what it will cost to get it in A-1 condition, you can decide if it's worth keeping. House air is not optional, it is mandatory. If your OTR air works, then your house air is a backup, but if the OTR does not work, the house air is your main system. Now the OTR air is way over powered for an RV use. It was designed to instantly cool a bus with a huge window and passenger heat load. I would guess that those loads could be an easy 40k to 50k BTU's (considering the 50 people alone would be more than 25k BTU's). Hence, the reason for removing your OTR air is that it doesn't work, is too costly to fix, and you don't really need it. The reason for keeping it is that it does work, is worth the repair and maintenance cost to you (remember, it will not be a one time fix), and is the first class system.

When we had our 1984 Eagle. The OTR did not work so I pulled it all out and sold the parts. It was in such a condition it would have been to costly to repair. On the 1991 Prevost that we now have, the OTR was working fine when we bought it just a little low on freon. I had it charged this summer, but it is low again so I will have it leak tested and repaired again. I like the OTR heat as well as it keeps the coach toasty and the driver comfortable even in cold temps.